In North Carolina, forest resources show the greatest potential for development of the biofuels industry.  Due to limited markets, North Carolina has a large inventory of standing timber.  For over five years, annual growth of the timber inventory has exceeded the annual timber usage.  This has further affected timber pricing, which in North Carolina was already among the lowest in the southern United States.  Currently, North Carolina’s timber inventory consists of 775 million green tons, 66% of which is hardwood and 34% is softwood.    

The infrastructure to sustainably harvest, replant, and transport the forest biomass has been in place for more than 100 years in North Carolina. Over 90% of the state’s forest land is privately owned, and the owners of forest biomass actively engage in the procurement, harvesting, and transportation of woody biomass.  Biofuels industry development provides opportunities for new markets for land owners as well as regional economic development.  In addition, federal and state forest service organizations and state forestry associations are involved in ensuring a sustainable supply of these forest resources.

While there is plentiful supply of woody biomass for biofuels production in North Carolina, new forest management practices will improve not only the economics, but also the environmental impact of woody biomass used for biofuels.  These forest management practices will include high density planting, intercropping, short rotation stands, and other practices that will increase the biomass volume grown on each acre.  By increasing the volume per acre, less land will be required to sustainably produce the volume of timber required to support the growth of the biofuels industry in North Carolina.

Facts about North Carolina's Forest Resources:

• There are 17.6 million acres of timberland in North Carolina
• Of this amount, there are almost 10 million acres in hardwoods, with the remainder pine and mixed pine/hardwood forests
• Ownership of these forests is predominantly in non-industrial ownership (with 13.9 million acres), followed by public ownership (at 1.9 million acres), and forest industry (at 1.7 million acres)
• Annual growing stock of all timber on North Carolina lands is approximately 15,929,259 tons
• Each year, 247,000 acres of timberland are harvested and retained as timberlands
• The biggest threat to timberlands in North Carolina is development, with an estimated 1.6 million acres lost since 1990

(Source: North Carolina Forestry Association, A Landowner’s Guide to Forestry in North Carolina, 2009)

Demand for timber in North Carolina is dominated by the traditional forest products industries: the pulp and paper industry utilizes pulpwood, and construction markets utilize saw timber.  These products are specified based on the size of the tree, with the smaller trees being used as pulpwood, larger trees used as chip-n-saw for composite panels, and the largest trees being used as saw timber.

Based on current forest products demand, pulpwood resembles the general species flexibility and physical properties acceptable for thermochemical biofuels production.  North Carolina currently has five pulp and paper mills using pulpwood as feedstock; four of these mills are located in the state’s coastal plains, and one is located in the mountains.

U.S. demand for paper and paper products has declined, and a worldwide shift in paper production has impacted North Carolina’s mills.  A number of machines have been idled, dismantled, and moved overseas.  In April 2009, Paper Age reported that U.S. paper and paperboard capacity edged down further in 2008, and cumulatively declined by 7.3% since its 2000 peak.  Additional increases in paper recycling have further reduced demand for virgin wood fibers as feedstock.

Also, North Carolina continues to build greater standing inventory of woody biomass growing stock.  Around the peak of timber demand for the construction and housing markets in 2006, nearly 45 million tons of wood were harvested in North Carolina for all markets, according to U.S. Forest Service 2006 FIA data.  Despite peak demand, North Carolina still increased its standing inventory in 2006 and grew nearly 54 million tons of timber – 20% more than was harvested.  Demand for forest products from the major market segments continues to decline across the board in North Carolina while supply increases, creating both a strong need and opportunity for biofuels development.

Upon evaluation, it is reasonable to conclude that new biofuels production capacity can be added across North Carolina without negatively impacting feedstock access and demand from existing pulp and paper operations.

Forestry residues are the limbs, tops, and other materials left on the forest floor after a conventional logging operation has cleared a managed forest – typically for the paper and lumber industries.  Forestry residues are often bulldozed into a pile and then burned in the field, but they offer one of the largest sources of unused biomass in the state, and can potentially be used for biofuels production. 

Forestry residues after a pine harvest operation.

 Forestry residues converted to wood chips in preparation for conversion to biofuels.

Listen to NC State University researcher Dr. Steve Kelley discuss forestry residues as a potential biofuels feedstock by clicking here.

Intercropping is a practice of planting different crops in the same field to optimize output economics. Current timber plantation management practices emphasize large-diameter saw timber productivity through frequent thinning and relatively large row spacing.  Intercropping Switchgrass between rows, for example, allows for significantly higher biomass output while maintaining consistent saw timber productivity.  Harvesting of energy grasses intercropped with actively managed saw timber plantations provides both a source for low-cost biomass as well as increased revenue to the plantation owner.

Over the next year, the Biofuels Center plans to establish trial plots to test intercropping on the Oxford Biofuels Campus.  The plots will be designed with trees (Pine and Sweetgum) planted in rows spaced at 10, 20, and 30 feet. Perennial grasses (Switchgrass and Giant Miscanthus) will be planted between the rows of trees.  The effect of the shading from the trees on the grasses and the competition from the grasses on young tree seedlings will be observed and evaluated.  The observation and evaluation will occur over the next 12 years, which is the projected productive lifespan of intercropped perennial grass.  The row spacing/competition and grass harvesting equipment will be evaluated to determine a logical row spacing of trees for intercropping.

There are a number of commercial tree species suitable for biofuels development in North Carolina, including softwoods (gymnosperms) and hardwoods (angiosperms), although some of the biofuels conversion processes are species-dependent. 

Loblolly Pine

Oaks

Yellow Poplars

Sweetgums

Red Maples

Sycamores

Cottonwood

Other Hardwood Species

One of the most important biofuels-ready species is the Loblolly Pine, a softwood tree:

• The Loblolly Pine’s natural range covers almost all of the Piedmont and Coastal Plains of North Carolina.  In addition to occurring naturally, the Loblolly is also artificially regenerated with an estimated 3.3 million acres of planted stands in North Carolina.  The Loblolly is the single most important species in the pulp/paper industry and also the largest species cut for dimensional lumber.  Large increases in the productivity of the Loblolly Pine have been made due to natural breeding, and the clonal Loblolly is currently being established.  Due to its ease in establishing planted stands, the Loblolly has been used in the establishment of forest stands on marginal agricultural lands.  Currently, the Biofuels Center is testing different lines of the Loblolly at the Biofuels Campus in Oxford.  These tests include various densities of stands grown on short rotations for maximized volume per acre.  Also, NC State University’s College of Natural Resources is evaluating the potential of the Loblolly Pine for biochemical conversion.

• There are other pine species that can be used for biofuels production, including the Shortleaf, Virginia, Longleaf, and Eastern White pines.

Among hardwood trees, there are several important species suitable for biofuels production:

• Oaks, both Red and White, are #2 to the Loblolly Pine as species of importance for biofuels development in North Carolina.  They are currently used in the pulp/paper industry but have even greater value in the lumber industry.  Oak stands naturally regenerate well and are difficult to establish with seedlings.  Most forestland in North Carolina’s Piedmont is classified as natural Oak/Pine forest.  (There are a number of other minor Oak species growing in North Carolina; click here for a full listing.)

• Yellow Poplars are found in all areas of North Carolina.  Classified as a soft hardwood, they grow well in fertile soils.  Yellow Poplars are primarily used in the pulp/paper industry and also in lumber production.

• Sweetgums grow in all areas of North Carolina.  It is an important species in the production of pulp/paper and Oriented Strand Board (OSB).  Larger trees are used for lumber production.  While most hardwood species regenerate naturally, Sweetgums can also be artificially regenerated by planting seedlings.  The Biofuels Center currently has demonstration plots of Sweetgum planted at the Oxford campus, testing lines and various spacing densities.

Sweetgum sapling, Biofuels Campus, Oxford, NC, May 2009.

• Red Maples have a natural range covering all of North Carolina.  This species is primarily used in the pulp/paper industry with limited use for lumber production. The Biofuels Center currently has demonstration plots of Red Maple planted at the Oxford campus, testing lines and various spacing densities. 

• Sycamores grow in all areas of North Carolina, especially in bottomlands.  It is an important species in the pulp/paper industry and OSB industry, and also has uses in lumber production.  The Biofuels Center currently has demonstration plots of Sycamore planted at the Oxford campus, testing lines and various spacing densities.

• Cottonwood have a natural range that covers almost all of the Piedmont and Coastal Plains of North Carolina.  Cottonwood are used primarily in the pulp/paper industry and have very limited use as a lumber species.  Similar to Sweetgums, Cottonwood can also be established by artificial regeneration.  Several Cottonwood species are currently being tested at the Biofuels Center's Oxford Research Station.

• While not as important as those listed above, other hardwood species will also contribute to biofuels development, including: Cherry, Hickory, Birch, Elm, Ash, Gum, Beech and Willow.